/**
 * Package: svgedit.draw
 *
 * Licensed under the Apache License, Version 2
 *
 * Copyright(c) 2011 Jeff Schiller
 */

// Dependencies:
// 1) jQuery
// 2) browser.js
// 3) svgutils.js

var svgedit = svgedit || {};

(function() {

if (!svgedit.draw) {
  svgedit.draw = {};
}

var svg_ns = "http://www.w3.org/2000/svg";
var se_ns = "http://svg-edit.googlecode.com";
var xmlns_ns = "http://www.w3.org/2000/xmlns/";

var visElems = 'a,circle,ellipse,foreignObject,g,image,line,path,polygon,polyline,rect,svg,text,tspan,use';
var visElems_arr = visElems.split(',');

var RandomizeModes = {
  LET_DOCUMENT_DECIDE: 0,
  ALWAYS_RANDOMIZE: 1,
  NEVER_RANDOMIZE: 2
};
var randomize_ids = RandomizeModes.LET_DOCUMENT_DECIDE;

/**
 * This class encapsulates the concept of a layer in the drawing
 * @param name {String} Layer name
 * @param child {SVGGElement} Layer SVG group.
 */
svgedit.draw.Layer = function(name, group) {
  this.name_ = name;
  this.group_ = group;
};

svgedit.draw.Layer.prototype.getName = function() {
  return this.name_;
};

svgedit.draw.Layer.prototype.getGroup = function() {
  return this.group_;
};


// Called to ensure that drawings will or will not have randomized ids.
// The current_drawing will have its nonce set if it doesn't already.
// 
// Params:
// enableRandomization - flag indicating if documents should have randomized ids
svgedit.draw.randomizeIds = function(enableRandomization, current_drawing) {
  randomize_ids = enableRandomization === false ?
    RandomizeModes.NEVER_RANDOMIZE :
    RandomizeModes.ALWAYS_RANDOMIZE;

  if (randomize_ids === RandomizeModes.ALWAYS_RANDOMIZE && !current_drawing.getNonce()) {
    current_drawing.setNonce(Math.floor(Math.random() * 100001));
  } else if (randomize_ids === RandomizeModes.NEVER_RANDOMIZE && current_drawing.getNonce()) {
    current_drawing.clearNonce();
  }
};

/**
 * This class encapsulates the concept of a SVG-edit drawing
 *
 * @param svgElem {SVGSVGElement} The SVG DOM Element that this JS object
 *     encapsulates.  If the svgElem has a se:nonce attribute on it, then
 *     IDs will use the nonce as they are generated.
 * @param opt_idPrefix {String} The ID prefix to use.  Defaults to "svg_"
 *     if not specified.
 */
svgedit.draw.Drawing = function(svgElem, opt_idPrefix) {
  if (!svgElem || !svgElem.tagName || !svgElem.namespaceURI ||
    svgElem.tagName != 'svg' || svgElem.namespaceURI != svg_ns) {
    throw "Error: svgedit.draw.Drawing instance initialized without a <svg> element";
  }

  /**
   * The SVG DOM Element that represents this drawing.
   * @type {SVGSVGElement}
   */
  this.svgElem_ = svgElem;
  
  /**
   * The latest object number used in this drawing.
   * @type {number}
   */
  this.obj_num = 0;
  
  /**
   * The prefix to prepend to each element id in the drawing.
   * @type {String}
   */
  this.idPrefix = opt_idPrefix || "svg_";
  
  /**
   * An array of released element ids to immediately reuse.
   * @type {Array.<number>}
   */
  this.releasedNums = [];

  /**
   * The z-ordered array of tuples containing layer names and <g> elements.
   * The first layer is the one at the bottom of the rendering.
   * TODO: Turn this into an Array.<Layer>
   * @type {Array.<Array.<String, SVGGElement>>}
   */
  this.all_layers = [];

  /**
   * The current layer being used.
   * TODO: Make this a {Layer}.
   * @type {SVGGElement}
   */
  this.current_layer = null;

  /**
   * The nonce to use to uniquely identify elements across drawings.
   * @type {!String}
   */
  this.nonce_ = "";
  var n = this.svgElem_.getAttributeNS(se_ns, 'nonce');
  // If already set in the DOM, use the nonce throughout the document
  // else, if randomizeIds(true) has been called, create and set the nonce.
  if (!!n && randomize_ids != RandomizeModes.NEVER_RANDOMIZE) {
    this.nonce_ = n;
  } else if (randomize_ids === RandomizeModes.ALWAYS_RANDOMIZE) {
    this.setNonce(Math.floor(Math.random() * 100001));
  }
};

svgedit.draw.Drawing.prototype.getElem_ = function(id) {
  if(this.svgElem_.querySelector) {
    // querySelector lookup
    return this.svgElem_.querySelector('#'+id);
  } else {
    // jQuery lookup: twice as slow as xpath in FF
    return $(this.svgElem_).find('[id=' + id + ']')[0];
  }
};

svgedit.draw.Drawing.prototype.getSvgElem = function() {
  return this.svgElem_;
};

svgedit.draw.Drawing.prototype.getNonce = function() {
  return this.nonce_;
};

svgedit.draw.Drawing.prototype.setNonce = function(n) {
  this.svgElem_.setAttributeNS(xmlns_ns, 'xmlns:se', se_ns);
  this.svgElem_.setAttributeNS(se_ns, 'se:nonce', n);
  this.nonce_ = n;
};

svgedit.draw.Drawing.prototype.clearNonce = function() {
  // We deliberately leave any se:nonce attributes alone,
  // we just don't use it to randomize ids.
  this.nonce_ = "";
};

/**
 * Returns the latest object id as a string.
 * @return {String} The latest object Id.
 */
svgedit.draw.Drawing.prototype.getId = function() {
  return this.nonce_ ?
    this.idPrefix + this.nonce_ +'_' + this.obj_num :
    this.idPrefix + this.obj_num;
};

/**
 * Returns the next object Id as a string.
 * @return {String} The next object Id to use.
 */
svgedit.draw.Drawing.prototype.getNextId = function() {
  var oldObjNum = this.obj_num;
  var restoreOldObjNum = false;

  // If there are any released numbers in the release stack, 
  // use the last one instead of the next obj_num.
  // We need to temporarily use obj_num as that is what getId() depends on.
  if (this.releasedNums.length > 0) {
    this.obj_num = this.releasedNums.pop();
    restoreOldObjNum = true;
  } else {
    // If we are not using a released id, then increment the obj_num.
    this.obj_num++;
  }

  // Ensure the ID does not exist.
  var id = this.getId();
  while (this.getElem_(id)) {
    if (restoreOldObjNum) {
      this.obj_num = oldObjNum;
      restoreOldObjNum = false;
    }
    this.obj_num++;
    id = this.getId();
  }
  // Restore the old object number if required.
  if (restoreOldObjNum) {
    this.obj_num = oldObjNum;
  }
  return id;
};

// Function: svgedit.draw.Drawing.releaseId
// Releases the object Id, letting it be used as the next id in getNextId().
// This method DOES NOT remove any elements from the DOM, it is expected
// that client code will do this.
//
// Parameters:
// id - The id to release.
//
// Returns:
// True if the id was valid to be released, false otherwise.
svgedit.draw.Drawing.prototype.releaseId = function(id) {
  // confirm if this is a valid id for this Document, else return false
  var front = this.idPrefix + (this.nonce_ ? this.nonce_ +'_' : '');
  if (typeof id != typeof '' || id.indexOf(front) != 0) {
    return false;
  }
  // extract the obj_num of this id
  var num = parseInt(id.substr(front.length));

  // if we didn't get a positive number or we already released this number
  // then return false.
  if (typeof num != typeof 1 || num <= 0 || this.releasedNums.indexOf(num) != -1) {
    return false;
  }
  
  // push the released number into the released queue
  this.releasedNums.push(num);

  return true;
};

// Function: svgedit.draw.Drawing.getNumLayers
// Returns the number of layers in the current drawing.
// 
// Returns:
// The number of layers in the current drawing.
svgedit.draw.Drawing.prototype.getNumLayers = function() {
  return this.all_layers.length;
};

// Function: svgedit.draw.Drawing.hasLayer
// Check if layer with given name already exists
svgedit.draw.Drawing.prototype.hasLayer = function(name) {
  for(var i = 0; i < this.getNumLayers(); i++) {
    if(this.all_layers[i][0] === name) return true;
  }
  return false;
};


// Function: svgedit.draw.Drawing.getLayerName
// Returns the name of the ith layer. If the index is out of range, an empty string is returned.
//
// Parameters:
// i - the zero-based index of the layer you are querying.
// 
// Returns:
// The name of the ith layer
svgedit.draw.Drawing.prototype.getLayerName = function(i) {
  if (i >= 0 && i < this.getNumLayers()) {
    return this.all_layers[i][0];
  }
  return "";
};

// Function: svgedit.draw.Drawing.getCurrentLayer
// Returns:
// The SVGGElement representing the current layer.
svgedit.draw.Drawing.prototype.getCurrentLayer = function() {
  return this.current_layer;
};

// Function: getCurrentLayerName
// Returns the name of the currently selected layer. If an error occurs, an empty string 
// is returned.
//
// Returns:
// The name of the currently active layer.
svgedit.draw.Drawing.prototype.getCurrentLayerName = function() {
  for (var i = 0; i < this.getNumLayers(); ++i) {
    if (this.all_layers[i][1] === this.current_layer) {
      return this.getLayerName(i);
    }
  }
  return "";
};

// Function: setCurrentLayer
// Sets the current layer. If the name is not a valid layer name, then this function returns
// false. Otherwise it returns true. This is not an undo-able action.
//
// Parameters:
// name - the name of the layer you want to switch to.
//
// Returns:
// true if the current layer was switched, otherwise false
svgedit.draw.Drawing.prototype.setCurrentLayer = function(name) {
  for (var i = 0; i < this.getNumLayers(); ++i) {
    if (name === this.getLayerName(i)) {
      if (this.current_layer != this.all_layers[i][1]) {
        this.current_layer.setAttribute("style", "pointer-events:none");
        this.current_layer = this.all_layers[i][1];
        this.current_layer.setAttribute("style", "pointer-events:all");
      }
      return true;
    }
  }
  return false;
};


// Function: svgedit.draw.Drawing.deleteCurrentLayer
// Deletes the current layer from the drawing and then clears the selection. This function 
// then calls the 'changed' handler.  This is an undoable action.
// Returns:
// The SVGGElement of the layer removed or null.
svgedit.draw.Drawing.prototype.deleteCurrentLayer = function() {
  if (this.current_layer && this.getNumLayers() > 1) {
    // actually delete from the DOM and return it
    var parent = this.current_layer.parentNode;
    var nextSibling = this.current_layer.nextSibling;
    var oldLayerGroup = parent.removeChild(this.current_layer);
    this.identifyLayers();
    return oldLayerGroup;
  }
  return null;
};

// Function: svgedit.draw.Drawing.identifyLayers
// Updates layer system and sets the current layer to the
// top-most layer (last <g> child of this drawing).
svgedit.draw.Drawing.prototype.identifyLayers = function() {
  this.all_layers = [];
  var numchildren = this.svgElem_.childNodes.length;
  // loop through all children of SVG element
  var orphans = [], layernames = [];
  var a_layer = null;
  var childgroups = false;
  for (var i = 0; i < numchildren; ++i) {
    var child = this.svgElem_.childNodes.item(i);
    // for each g, find its layer name
    if (child && child.nodeType === 1) {
      if (child.tagName === "g") {
        childgroups = true;
        var name = $("title",child).text();
        
        // Hack for Opera 10.60
        if(!name && svgedit.browser.isOpera() && child.querySelectorAll) {
          name = $(child.querySelectorAll('title')).text();
        }

        // store layer and name in global variable
        if (name) {
          layernames.push(name);
          this.all_layers.push( [name,child] );
          a_layer = child;
          svgedit.utilities.walkTree(child, function(e){e.setAttribute("style", "pointer-events:inherit");});
          a_layer.setAttribute("style", "pointer-events:none");
        }
        // if group did not have a name, it is an orphan
        else {
          orphans.push(child);
        }
      }
      // if child has is "visible" (i.e. not a <title> or <defs> element), then it is an orphan
      else if(~visElems_arr.indexOf(child.nodeName)) {
        var bb = svgedit.utilities.getBBox(child);
        orphans.push(child);
      }
    }
  }
  
  // create a new layer and add all the orphans to it
  var svgdoc = this.svgElem_.ownerDocument;
  if (orphans.length > 0 || !childgroups) {
    var i = 1;
    // TODO(codedread): What about internationalization of "Layer"?
    while (layernames.indexOf(("Layer " + i)) >= 0) { i++; }
    var newname = "Layer " + i;
    a_layer = svgdoc.createElementNS(svg_ns, "g");
    var layer_title = svgdoc.createElementNS(svg_ns, "title");
    layer_title.textContent = newname;
    a_layer.appendChild(layer_title);
    for (var j = 0; j < orphans.length; ++j) {
      a_layer.appendChild(orphans[j]);
    }
    this.svgElem_.appendChild(a_layer);
    this.all_layers.push( [newname, a_layer] );
  }
  svgedit.utilities.walkTree(a_layer, function(e){e.setAttribute("style","pointer-events:inherit");});
  if (a_layer.getAttribute("data-locked") === "true") {
    this.current_layer = this.all_layers.slice(-2)[0][1]
  }
  else {
    this.current_layer = a_layer
  }
  this.current_layer.setAttribute("style","pointer-events:all");
};

// Function: svgedit.draw.Drawing.createLayer
// Creates a new top-level layer in the drawing with the given name and 
// sets the current layer to it.
//
// Parameters:
// name - The given name
//
// Returns:
// The SVGGElement of the new layer, which is also the current layer
// of this drawing.
svgedit.draw.Drawing.prototype.createLayer = function(name) {
  var svgdoc = this.svgElem_.ownerDocument;
  var new_layer = svgdoc.createElementNS(svg_ns, "g");
  var layer_title = svgdoc.createElementNS(svg_ns, "title");
  new_layer.id = name.replace(" ", "_")
  layer_title.textContent = name;
  new_layer.appendChild(layer_title);
  this.svgElem_.appendChild(new_layer);
  this.identifyLayers();
  return new_layer;
};

// Function: svgedit.draw.Drawing.getLayerVisibility
// Returns whether the layer is visible.  If the layer name is not valid, then this function
// returns false.
//
// Parameters:
// layername - the name of the layer which you want to query.
//
// Returns:
// The visibility state of the layer, or false if the layer name was invalid.
svgedit.draw.Drawing.prototype.getLayerVisibility = function(layername) {
  // find the layer
  var layer = null;
  for (var i = 0; i < this.getNumLayers(); ++i) {
    if (this.getLayerName(i) === layername) {
      layer = this.all_layers[i][1];
      break;
    }
  }
  if (!layer) return false;
  return (layer.getAttribute('display') != 'none');
};

// Function: svgedit.draw.Drawing.setLayerVisibility
// Sets the visibility of the layer. If the layer name is not valid, this function return 
// false, otherwise it returns true. This is an undo-able action.
//
// Parameters:
// layername - the name of the layer to change the visibility
// bVisible - true/false, whether the layer should be visible
//
// Returns:
// The SVGGElement representing the layer if the layername was valid, otherwise null.
svgedit.draw.Drawing.prototype.setLayerVisibility = function(layername, bVisible) {
  if (typeof bVisible != typeof true) {
    return null;
  }
  // find the layer
  var layer = null;
  for (var i = 0; i < this.getNumLayers(); ++i) {
    if (this.getLayerName(i) === layername) {
      layer = this.all_layers[i][1];
      break;
    }
  }
  if (!layer) return null;
  
  var oldDisplay = layer.getAttribute("display");
  if (!oldDisplay) oldDisplay = "inline";
  layer.setAttribute("display", bVisible ? "inline" : "none");
  return layer;
};


// Function: svgedit.draw.Drawing.getLayerOpacity
// Returns the opacity of the given layer.  If the input name is not a layer, null is returned.
//
// Parameters: 
// layername - name of the layer on which to get the opacity
//
// Returns:
// The opacity value of the given layer.  This will be a value between 0.0 and 1.0, or null
// if layername is not a valid layer
svgedit.draw.Drawing.prototype.getLayerOpacity = function(layername) {
  for (var i = 0; i < this.getNumLayers(); ++i) {
    if (this.getLayerName(i) === layername) {
      var g = this.all_layers[i][1];
      var opacity = g.getAttribute('opacity');
      if (!opacity) {
        opacity = '1.0';
      }
      return parseFloat(opacity);
    }
  }
  return null;
};

// Function: svgedit.draw.Drawing.setLayerOpacity
// Sets the opacity of the given layer.  If the input name is not a layer, nothing happens.
// If opacity is not a value between 0.0 and 1.0, then nothing happens.
//
// Parameters:
// layername - name of the layer on which to set the opacity
// opacity - a float value in the range 0.0-1.0
svgedit.draw.Drawing.prototype.setLayerOpacity = function(layername, opacity) {
  if (typeof opacity != typeof 1.0 || opacity < 0.0 || opacity > 1.0) {
    return;
  }
  for (var i = 0; i < this.getNumLayers(); ++i) {
    if (this.getLayerName(i) === layername) {
      var g = this.all_layers[i][1];
      g.setAttribute("opacity", opacity);
      break;
    }
  }
};

})();
